643849368 has 32 divisors (see below), whose sum is σ = 1630003200. Its totient is φ = 211899168.

The previous prime is 643849357. The next prime is 643849379. The reversal of 643849368 is 863948346.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (643849357) and next prime (643849379).

It is a self number, because there is not a number n which added to its sum of digits gives 643849368.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 167896 + ... + 171687.

It is an arithmetic number, because the mean of its divisors is an integer number (50937600).

Almost surely, 2^643849368 is an apocalyptic number.

It is an amenable number.

643849368 is an abundant number, since it is smaller than the sum of its proper divisors (986153832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643849368 is a wasteful number, since it uses less digits than its factorization.

643849368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339671 (or 339667 counting only the distinct ones).

The product of its digits is 2985984, while the sum is 51.

The square root of 643849368 is about 25374.1870411645. The cubic root of 643849368 is about 863.4981760966.

The spelling of 643849368 in words is "six hundred forty-three million, eight hundred forty-nine thousand, three hundred sixty-eight".